1. Field of the Invention
The present invention pertains to processes for the polymerization of olefins, notably strained ring polycyclic olefins, particularly dicyclopentadiene, as well as to the corresponding polymeric reaction product. The invention utilizes metathesis polymerization in combination with one or more of a variety of other catalysts selected from the group consisting of: a Lewis acid catalyst and cocatalyst, an anionic catalyst, a free radical initiator, and a hydrosilation catalyst. The processes of the present invention are particularly suited to manufacturing plastic articles via reaction injection molding (i.e. "RIM").
2. Background and Relevant Information
Preparation of thermoset cycloolefin polymers via metathesis catalysis is a relatively recent development in the polymer art. Klosiewicz, in U.S. Pat. Nos. 4,400,340 and 4,520,181, teaches preparation of cycloolefins via a twostream reaction injection molding technique wherein a first stream, comprising a metathesis polymerizable olefin (such as dicyclopentadiene) in admixture with a metathesis catalyst, and a second stream, comprisihg a metathesis polymerizable olefin (such as dicyclopentadiene) in admixture with metathesis catalyst activator, are combined in a mix head and immediately injected into a mold where, within a matter of seconds, polymerization and molding to a permanently fixed shape take place simultaneously. Klosiewicz also teaches the use of a reaction rate moderator in the activator stream to delay the catalyst activation until the reaction mass is totally within the mold. Klosiewicz states that the catalyst can be a tungsten halide or a tungsten oxyhalide, and that the activator can be tetrabutyl tin, or an alkylaluminum compound, and that the reaction rate moderator can be an ester, ether, ketone or nitrile.
U.S. Pat. No. 4,835,230 (to N.P. KHASAT et al.) relates to the use of a cationic polymerization initiator in the preparation of a thermoset polymer. Cationic polymerization initiators disclosed include protonic acids, Lewis acids and other cation generators such as alkyl perchlorates and ionizing radiation, and it is further disclosed that the cationic polymerization initiator can be used alone or in conjunction with a cocatalyst. KHASAT et al. utilizes a plurality of reactant streams in the polymerization of dicyclopentadiene, especially for RIM. KHASAT et al. states that the number of applications for thermoset polydicyclopentadiene has been somewhat limited because of the distinctive odor of the residual dicyclopentadiene monomer. Finally, KHASAT et al. states that the use of a cationic polymerization initiator can increase the glass transition temperature (T.sub.g) and polymer heat deflection temperature (HDT) of thermoset dicyclopentadiene polymers and copolymers, and reduce residual monomer content without reducing impact strength.
U.S. Pat. No. 4,481,344, to Newburg (NEWBURG), relates to a method for making thermoset poly(dicyclopentadiene), and to the product so produced. NEWBURG states that although thermoset poly(dicyclopentadiene) is well suited for a wide variety of applications, particularly as an engineering plastic, there are a number of applications in which its use has been somewhat limited due to the distinctive odor of the residual dicyclopentadiene monomer. NEWBURG describes a twopart metathesis catalyst system in which the first part comprises a metathesis catalyst, and the second part comprises an activator, and wherein at least one part comprises a halogen-containing hydrocarbyl additive. The hydrocarbyl additive contains at least one trihalogen-substituted atom or at least one activated halogen atom. NEWBURG's Table I discloses various hydrocarbyl additives, and Table II provides results in terms of residual dicyclopentadiene monomer in various poly(dicyclopentadiene) products produced using various hydrocarbyl additives.
European Patent Application 0,374,997 relates to the polymerization of cyclic olefins in the presence of a catalyst comprising (a) a transition metal compound, (b) a co-catalyst, and (c) a boron halide compound. This application states that this catalyst has been found to exhibit high activity in the polymerization of dicyclopentadiene, and high conversion in a reaction injection molding process having a short induction time and relatively low polymerization temperature.